What are the characteristics and side effects of reserpine? The antihypertensive effect of reserpine is slow and mild after oral administration, and slowly disappears after drug withdrawal. It takes effect in 3-7 days after oral administration, reaches its peak in 3-4 weeks, and blood pressure rises in 2-6 weeks after drug withdrawal. The drug has been widely used in mild to moderate hypertension, especially in combination with thiazide diuretics, and it is one of the main components of compound antihypertensive drugs commonly used at present. The usual oral dosage is 0.25-0.5 mg per day. The dosage of intramuscular injection or intravenous injection is 0.5- 1.0 mg. Blood pressure began to drop about 30-60 minutes after injection, and the maximum effect was 3 hours. Therefore, repeated injections should be carried out after 3 hours. There are many adverse reactions of reserpine. At present, new antihypertensive drugs with more advantages have been put on the market, and this drug has been rarely used in the treatment of hypertension. Common adverse reactions include nasal congestion, dry mouth, depression, hyperacidity, diarrhea, rash and so on. In large doses, flushing, arrhythmia, angina pectoris-like syndrome, bradycardia and occasionally Parkinson's syndrome may occur. It should be noted that patients with depression or medical history, patients with ulcer disease, acute localized enteritis, ulcerative colitis and Parkinson's syndrome are prohibited.